Pattern control device for shotguns



Feb. 1, 1955 w. 1.. FINLAY ETAL PATTERN CONTROL DEVICE FOR SHOTGUNS 2 Sheets-Sheet 1 Filed Sept. 9, 1950 INVENTORS LTER L. F/NLAY BERT T. CATL/N By G/LBER T 1 HU TCH/NSUN ATTORN Y5 1955 w. 1.. FINLAY ETAL 2,700,839

PATTERN CONTROL DEVICE FOR SHOTGUNS Filed Sept. 9, 1950 2 Sheets-Sheet 2 INVENTORS WALTER L. F/NLAY ROBERT 7i CATL/N By GILBERT E. HurcH/Nso/v ATTORNEYS United States Patent PATTERN CONTROL DEVICE FOR SHOTGUNS Walter L. Finlay, Fairfield, Robert T. Catlin, Stratford, and Gilbert E. Hutchinson, Nichols, Conn., assignors to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Application September 9, 1950, Serial No. 183,996

3 Claims. (Cl. 42-79) This invention relates to devices for controlling the extent to which a charge of shot will be dispersed upon emergence from the barrel of a shotgun, and has particular reference to an adjustable type of such device.

Shot patterns are usually evaluated quantitatively on the basis of the percentage of the total shot charge impacting within the circumference of a 30" circle when fired from a range of 40 yards. A gun which will place 70% or more of its shot within that area is said to throw a close or full choke pattern and would be most useful for long range shooting at migratory birds or in the sport of trap shooting. At what has been regarded the other extreme, we find the cylinder bored barrel which places about 40% of its shot within the 30" circle and is said to throw an open or cylinder pattern. Such a barrel would be most useful at close range and with swiftly moving or erratic targets. Between these extremes there are a number of intermediate degrees of pattern, each of which is regarded by some sportsman as ideal for his particular purpose.

Since comparatively few sportsmen can afford to own separate guns for every type of shooting or even extra barrels for a single gun, there has been widespread demand for adjustable pattern devices. This demand has been filled in part by devices of the sort shown in patents to E. Field White, including No. 1,892,522, Reissue No. 20,958, and No. 2,335,138.

Qualitatively, patterns are judged on the basis of uniformity of distribution of the shot charge and thus far no adjustable pattern device has been produced which would throw uniform patterns throughout the entire range of adjustment of the device. This has been particularly true when such devices are used at open pattern settings when the central portion of the pattern is materially denser than the outer edges.

Our objective is the production of a pattern control device which is adjustable over the full range of usable patterns and one which yields uniformly distributed patterns at any setting.

We contemplate that the best means of obtaining this effect is by the use of a barrel which is formed with a constriction suitable for producing a close or full choke pattern in combination with a rifled tubular section through which the shot charge also passes, the rifled section being of itself adjustable to vary the effect of the rifling upon the shot passing therethrough. The rifled section may be made adjustable as to its internal diameter or as to the pitch of the rifling with equivalent results. Further, the rifled section may precede or follow the constriction of the barrel without material effect upon the results obtained, although generally the most practical mechanical arrangement will place the rifled section in front of the constriction and vary the effect of the rifling by varying the effective diameter of the rifled section.

The exact nature of our device as well as other objects and advantages thereof will become more apparent after considering the following specification referring to the drawings, in which:

Fig. 1 is a fragmentary side elevation, partially in section, showing a portion of a barrel having attached thereto the preferred embodiment of our device.

2 is a cross-sectional view on the line 2-2 of Fig. 3 is a view similar to Fig. 1, showing a modified form.

Fig. 4 is a longitudinal section view showing a modified form of our device.

. 8 Fig. 5 is an elevational view corresponding to Fig. 4.

2,700,839 Patented Feb. 1, 1955 Fig. 6 is a longitudinal sectional view of another modified form of our device.

According to this invention, the shot are first concentrated by passing through a fixed constriction, to produce a dense pattern. Thereafter, the shot are caused to traverse a tubular member which may be so varied or adjusted with respect to the concentrated shot column as to produce any desired amount of spread with an extraordinary uniformity of pattern throughout the target area. Referring to Fig. 1, integral with a gun barrel 10 is a tapering choke section 11 communicating with a short straight section 12. The dimensions and proportions of sections 11 and 12 are such as to deliver a dense or full choke pattern. Secured to or integral with the barrel 10 is a member 13 comprising a number of slots 14, preferably spiral, which separate section 13 into a number of separate spirally extending fingers 15. The interior surfaces of fingers 15 comprise spiral grooves 16 preferably of pitch similar to the fingers 15 which are not unlike the rifling grooves ordinarily applied to the interior of a gun barrel intended for the passage of a single projectile. The land diameter of member 13 when fully open is not less and preferably slightly greater than the diameter of the constricted throat 12, so that when a dense or full choke pattern is desired, the full charge traverses the member 13 without contact with its interior surface. Adjustably mounted on the exterior of member 13 is a sleeve 17 having an interior configuration which is so related to the exterior configuration of member 13 that a longitudinal adjustment of sleeve 17 effects an inward displacement of fingers 15 in a manner familiar in the art. By such inward displacement, the rifled interior surface of fingers 15 can be made to contact the shot column to any desired extent-the greater the amount of such contact, the greater spread of the pattern. This effect is the reverse of that secured in the absence of the rifling 16. If the interior surface or part 13 is smooth, the greater the constriction the more dense the pattern. The provision of the rifling has the reverse effect, contact of the shot with the rifling producing a turbulence of such a character as to spread the shot. Not only is the pattern spread, but there is secured in all parts of the pattern a measure of uniformity which is not attained in any prior art devices. The enrichment of the outer zones of the pattern is particularly marked.

In the form of the invention shown in Fig. 3, the gun barrel 20 is provided with the usual tapered choke section 21 and short circuited throat 22 through which the shot charge is delivered to a muzzle section 23 either integral with or rigidly secured to the barrel. Whereas, the Fig. 1 form of the invention contemplates varying the constriction within a rifled section, the Fig. 3 form contemplates varying the pitch of the rifling. To this end, the rifling members are separate strips or wires 24 suitably secured to the barrel interior at 25 adjacent the throat section 22. The forward ends of the rifling members 24 are turned outwardly and secured at 26 in a sleeve member 27 adjustably held on the barrel exterior by suitable means such as the threaded connection 28. The exterior surface of sleeve member 27 may be provided with milling, checkering, or other means, for its ready manipulation, and with a releasable detent 29 engageable in recesses 30 in the exterior of the barrel. To secure a full choke pattern, sleeve 27 is so adjusted that the rifiing members 24 lie in parallel with the axis of the gun barrel 20 and thus have a minimum of contact with the shot charge, so that the charge passes through the section 23 without modification of the characteristics imposed upon it by the choke section 21. Any desired amount of pattern spread can be secured by appropriately rotating the sleeve 27 to vary the angle of rifling members 24 with respect to the length of the gun barrelthe greater the angle or twilst of these rifling members, the greater the pattern sprea In the form of the invention shown in Fig. 4, the gun barrel 30 is, as in the other forms, provided with a tapered choke section 31 and a short generally cylindrical throat 32 through which the shot charge is delivered to a rifled section of variable pitch indicated generally by the numeral 33. In this instance the rifled section comprises an being secured to a spring retainer 35 by a suitable brazing or soldering operation. The retainer 35 is secured non-rotatably but with limited freedom for longitudinal movement within a sleeve 36 threadably received on the end of the barrel and snugly enclosing the spring 34. At the other end of the spring, the end turn is brazed, or otherwise secured, to an adjustable retainer ring 37 provided with a detent 38 engageable in selected positions in a notched slot 39 formed in the sleeve. An inturned flange 40 on the forward end of the sleeve is arranged to engage the front face of the retainer ring 37. Obviously, with the detent 38 positioned in any desired one of the retainer notches, the assembly may be tightened by screwing the sleeve rearwardly on the barrel and thus clamping the assembly of spring and retainer rings between the end face of the barrel and the flange 40. With the spring detent 38 positioned in one of its extreme positions, a series of equally spaced axially parallel grooves 41 may be formed in the inner surface of the spring 34. A coiled spring of this character will, when one end turn is rotated by any given amount relative to the opposite end turn, distribute this deflection in substantially equal increments per turn over the entire length of the spring. When the sleeve has been loosened on the barrel sufliciently to permit the detent to be moved to a position opposite another notch in the slot 39, for example, the opposite extreme, it will be found that the grooves 41 are no longer axially parallel but define a spiral rifling in the inner surface of the spring. The inside diameter of the spring section should not be less, and preferably should be slightly greater, than the least diameter of the throat 32. The length of this section should not be greater than, and preferably should be considerably less than, 2.0 inches or the efiect noted in the co-pending application of Walter L. Finlay, application Serial Number 685,238, filed July 20, 1946, may prevent maximum concentration of shot even with a straight setting of the grooves in the rifling. Adjustments which increase the effective pitch of the rifled section produce the spreading in the pattern noted with the variable diameter rifling and the variable pitch wire rifling.

Fig. 6 shows a modification in which the relationship of rifled tubular section and choke shown in the other forms has been reversed. In this form the barrel 50 is bored to true cylinder form. At its muzzle a rigidly attached or integral tubular assembly 53 is provided. This assembly consists of generally spiral fingers 55 separated by spiral cuts 54. Preferably, this section has a slightly larger inside diameter than the cylinder bored barrel and is formed to define a plurality of spiral rifling grooves 56. A sleeve 57 is threaded on the outside of the rifled tubular section and provided with conical shoulders 59 arranged to constrict and reduce the diameter of the rifled section. On the forward end of the sleeve there is formed an extension formed to provide a tapered choke section 51 and a short generally cylindrical throat 52 of dimensions appropriate for full choke patterns.

With this arrangement a shot may be fired with the sleeve set to allow the rifled section to remain out of contact with the passing shot and the charge will be reconstructed in the choke section and issue from the throat 52 as a full choke pattern. As the diameter of the rifled section is reduced, a measure of rotation is given to the passing charge and a turbulence induced which cannot be overcome by the choke section. It is possible in this way to produce widely and uniformly scattered patterns placing 40% or less of the shot in a reference 30 circle even though the shot has passed through the full choke constriction, and any intermediate pattern desired may be as readily secured.

It is thus seen that the invention contemplates the control of shotgun patterns by varying a characteristic of a rifled section which is traversed by a shot charge that also traverses a constriction suitable for a full choke pattern. By this means, patterns of any desired degree of spread and of unprecedented uniformity can be secured.

Although the invention has been illustrated by reference to certain specific embodiments, it should be understood that we consider our invention to be limited only by the scope of the claims appended hereto.

We claim:

1. A shotgun barrel having integral therewith a unitary pattern control device, said device comprising a throat section that is progressively constricted in the direction of shot movement, a rifled section rigidly and non-removably secured to said throat section, and means for displacing elements of said rifled section transversely to the axis of said barrel, thereby altering the eflect of said rifled section on a shot charge passing therethrough.

2. Apparatus according to claim 1, in which said rifled section comprises a plurality of longitudinally extending fingers and said means is effective to displace portions of said fingers in a direction transverse to the axis of said barrel.

3. Apparatus according to claim 2, in which said throat section is disposed between said barrel and said rifled section.

References Cited in the file of this patent UNITED STATES PATENTS Alsop Dec. 16, 1862 Fosberry Oct. 27, 1885 White Dec. 27, 1932 

